Coordinator + Repeater Xbee + End device configuration

Question

I am trying to work on a Xbee based solution for transferring data from with in a specified area.I am using Xbee865LP for the same project.

Now what i want to implement is Make one device act as

1. Coordinator - Combination of Xbee + RPI
2. End_device - A microcontroller + Xbee + Some sensor
3. Repeater - A Stand alone Xbee.

and make Controller talk to end device via repeater. Now as i was understanding earlier that we can just set DH and DL of coordinator and end device to their SH and SL, put up a repeater in-between and it will work out. But it didn't happen as i thing flow of data might might be taking place like this(if it would have happened)

Coordinator send data to repeater(with coordinator DL and DH being fixed to that of repeater) and repeater will send data to end device(with repeater DL and DH being set to that of end device). So it is quite easy to work if flow of information/data need to take place like this Coordinator-->Repeater-->End device.

Now my first question is what if data/information need to flow in opposite manner i.e. End-device-->Repeater-->Coordinator. So a simple answer is we can use API mode, first set the repeater DL and DH to SL and SH of end_device , send data and then set the DL and DH of repeater to SL and SH of coordinator. But i dont want to work in API mode.

My next question is , isn't there any way, with which we can simply increase the range of transmission between Coordinator and End-device? Probably making repeater work in a mode,in which it simply relay the data which it received ? I know its a stupid question, when i know that it cannot even receive the data when the data have DL and Dl of end device and not that of repeater. Can any one suggest me any alternatives?

Answer 1

You can have several devices communication with each other in all directions. What you need to do is to set all the XBee's to the same PAN ID, instead of configuring the destination physical addresses of the modules. The device you want to act as "repeater", should be a "router". If the end device, the router and the coordinator are sharing the same PAN ID, they will communicate to each other. So the end device will communicate through the router when needed, but if in range, it can also communitcate directly to the coordinator. The ZigBee protocol will manage that for you!